/*
 * Copyright (c) 2006, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.util.zip;

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Implements an output stream filter for uncompressing data stored in the
 * "deflate" compression format.
 *
 * @author David R Tribble (david@tribble.com)
 * @see InflaterInputStream
 * @see DeflaterInputStream
 * @see DeflaterOutputStream
 * @since 1.6
 */

public class InflaterOutputStream extends FilterOutputStream {

  /**
   * Decompressor for this stream.
   */
  protected final Inflater inf;

  /**
   * Output buffer for writing uncompressed data.
   */
  protected final byte[] buf;

  /**
   * Temporary write buffer.
   */
  private final byte[] wbuf = new byte[1];

  /**
   * Default decompressor is used.
   */
  private boolean usesDefaultInflater = false;

  /**
   * true iff {@link #close()} has been called.
   */
  private boolean closed = false;

  /**
   * Checks to make sure that this stream has not been closed.
   */
  private void ensureOpen() throws IOException {
    if (closed) {
      throw new IOException("Stream closed");
    }
  }

  /**
   * Creates a new output stream with a default decompressor and buffer
   * size.
   *
   * @param out output stream to write the uncompressed data to
   * @throws NullPointerException if {@code out} is null
   */
  public InflaterOutputStream(OutputStream out) {
    this(out, new Inflater());
    usesDefaultInflater = true;
  }

  /**
   * Creates a new output stream with the specified decompressor and a
   * default buffer size.
   *
   * @param out output stream to write the uncompressed data to
   * @param infl decompressor ("inflater") for this stream
   * @throws NullPointerException if {@code out} or {@code infl} is null
   */
  public InflaterOutputStream(OutputStream out, Inflater infl) {
    this(out, infl, 512);
  }

  /**
   * Creates a new output stream with the specified decompressor and
   * buffer size.
   *
   * @param out output stream to write the uncompressed data to
   * @param infl decompressor ("inflater") for this stream
   * @param bufLen decompression buffer size
   * @throws IllegalArgumentException if {@code bufLen <= 0}
   * @throws NullPointerException if {@code out} or {@code infl} is null
   */
  public InflaterOutputStream(OutputStream out, Inflater infl, int bufLen) {
    super(out);

    // Sanity checks
    if (out == null) {
      throw new NullPointerException("Null output");
    }
    if (infl == null) {
      throw new NullPointerException("Null inflater");
    }
    if (bufLen <= 0) {
      throw new IllegalArgumentException("Buffer size < 1");
    }

    // Initialize
    inf = infl;
    buf = new byte[bufLen];
  }

  /**
   * Writes any remaining uncompressed data to the output stream and closes
   * the underlying output stream.
   *
   * @throws IOException if an I/O error occurs
   */
  public void close() throws IOException {
    if (!closed) {
      // Complete the uncompressed output
      try {
        finish();
      } finally {
        out.close();
        closed = true;
      }
    }
  }

  /**
   * Flushes this output stream, forcing any pending buffered output bytes to be
   * written.
   *
   * @throws IOException if an I/O error occurs or this stream is already closed
   */
  public void flush() throws IOException {
    ensureOpen();

    // Finish decompressing and writing pending output data
    if (!inf.finished()) {
      try {
        while (!inf.finished() && !inf.needsInput()) {
          int n;

          // Decompress pending output data
          n = inf.inflate(buf, 0, buf.length);
          if (n < 1) {
            break;
          }

          // Write the uncompressed output data block
          out.write(buf, 0, n);
        }
        super.flush();
      } catch (DataFormatException ex) {
        // Improperly formatted compressed (ZIP) data
        String msg = ex.getMessage();
        if (msg == null) {
          msg = "Invalid ZLIB data format";
        }
        throw new ZipException(msg);
      }
    }
  }

  /**
   * Finishes writing uncompressed data to the output stream without closing
   * the underlying stream.  Use this method when applying multiple filters in
   * succession to the same output stream.
   *
   * @throws IOException if an I/O error occurs or this stream is already closed
   */
  public void finish() throws IOException {
    ensureOpen();

    // Finish decompressing and writing pending output data
    flush();
    if (usesDefaultInflater) {
      inf.end();
    }
  }

  /**
   * Writes a byte to the uncompressed output stream.
   *
   * @param b a single byte of compressed data to decompress and write to the output stream
   * @throws IOException if an I/O error occurs or this stream is already closed
   * @throws ZipException if a compression (ZIP) format error occurs
   */
  public void write(int b) throws IOException {
    // Write a single byte of data
    wbuf[0] = (byte) b;
    write(wbuf, 0, 1);
  }

  /**
   * Writes an array of bytes to the uncompressed output stream.
   *
   * @param b buffer containing compressed data to decompress and write to the output stream
   * @param off starting offset of the compressed data within {@code b}
   * @param len number of bytes to decompress from {@code b}
   * @throws IndexOutOfBoundsException if {@code off < 0}, or if {@code len < 0}, or if {@code len >
   * b.length - off}
   * @throws IOException if an I/O error occurs or this stream is already closed
   * @throws NullPointerException if {@code b} is null
   * @throws ZipException if a compression (ZIP) format error occurs
   */
  public void write(byte[] b, int off, int len) throws IOException {
    // Sanity checks
    ensureOpen();
    if (b == null) {
      throw new NullPointerException("Null buffer for read");
    } else if (off < 0 || len < 0 || len > b.length - off) {
      throw new IndexOutOfBoundsException();
    } else if (len == 0) {
      return;
    }

    // Write uncompressed data to the output stream
    try {
      for (; ; ) {
        int n;

        // Fill the decompressor buffer with output data
        if (inf.needsInput()) {
          int part;

          if (len < 1) {
            break;
          }

          part = (len < 512 ? len : 512);
          inf.setInput(b, off, part);
          off += part;
          len -= part;
        }

        // Decompress and write blocks of output data
        do {
          n = inf.inflate(buf, 0, buf.length);
          if (n > 0) {
            out.write(buf, 0, n);
          }
        } while (n > 0);

        // Check the decompressor
        if (inf.finished()) {
          break;
        }
        if (inf.needsDictionary()) {
          throw new ZipException("ZLIB dictionary missing");
        }
      }
    } catch (DataFormatException ex) {
      // Improperly formatted compressed (ZIP) data
      String msg = ex.getMessage();
      if (msg == null) {
        msg = "Invalid ZLIB data format";
      }
      throw new ZipException(msg);
    }
  }
}
